Colossians 1:5-6 For the hope which is laid up for you in heaven, whereof ye heard before in the word of the truth of the gospel; Which is come to you, as it is in all the world; and bringeth forth fruit, as it doth also in you, since the day ye heard of it, and knew the grace of God in truth:

The word of truth can be heard. It can be heard when reading the Bible. It can be heard when hearing another Christian speaking of the gospel from the Bible. It can be heard when the Holy Spirit brings Scripture and the principles of Scripture to our memory. The Fruit of the Spirit, which is righteousness, springs forth from the moment we were born again, which was the moment we knew the grace of God. Notice that we did not know about the grace of God, but we truly knew the grace of God.

Note that this follows God's process. God speaks and we hear. Then faith comes and gives us access to grace. Grace comes in and does the works in us.

(some caveats about hearing God's Voice)